Thrips associated with the environs of onion fields in Colorado

In connection with research being conducted on Iris Yellow Spot Virus, of which Thrips tabaci is a known vector, thrips were sampled from onion fields in Colorado and from adjacent fields of wheat and alfalfa. Thrips were sampled between May and August for two years. We describe the species of thrips identified from these fields, including resident species and transients migrating from adjacent crops, and changes in species composition over time.